Comparison of sorption heats from isosteric and calorimetric experiments for nitrogen, oxygen and carbon dioxide on zeolites of types LTA and FAU

Isosteric heats of sorption measured directly by sorption isosteric and calorimetric methods are compared for nitrogen and oxygen on CaA and carbon dioxide on NaX zeolite. The concentration dependences of isosteric sorption heats obtained by these methods show similar shapes. Depending on concentration ranges, the heats from the isosteric method are somewhat smaller than those from calorimetry. The discrepancy amounts to 2 kJ/mol, at the most. Since the same materials were used for all experiments, the source of this disagreement remains unknown.